(239) Characterization of PAPi in Patients With ECMO Following Pulmonary Thromboendarterectomy

Introduction: Pulmonary thromboendarterectomy (PTE) is a surgical treatment to prevent right ventricular remodeling. However, perioperative complications such as acute right ventricular failure (RVF), reperfusion pulmonary edema and massive pulmonary hemorrhage can indicated ECMO. The pulmonary artery pulsatility index (PAPi) less than 1.6 predicts acute right ventricular failure. This study aims to characterize PAPi behavior in post-PTE patients and assess its utility in predicting ECMO support needs

Methods: This retrospective case series. We reviewed records of patients with chronic thromboembolic disease who underwent PTE from September 2013 to January 2020 and required ECMO. A descriptive analysis of the variables was conducted. Qualitative variables were included as frequencies and percentages, while quantitative variables were presented as means or medians and standard deviations or interquartile ranges. Group comparisons were made using the Student's t-test for normally distributed data and the Mann-Whitney U test for non-normally distributed data. Statistical significance was defined as P < 0.05. SPSS (IBM) was used for the analysis

Results: 48 patients were included, with a median age of 56 years. The median PAPi for those requiring ECMO support was 4.7 versus 4.3 for those not needing ECMO. Pulmonary vascular resistance and cardiac index in ECMO-supported patients were 6.5 ± 3.4 Wood and 2.8 L/min/m², compared to 8.5 ± 5.5 Wood and 2.6 L/min/m² in non-ECMO patients (p=0.65, p=0.69). Cardiopulmonary bypass time was significantly longer in ECMO-supported patients (305 ± 44 min vs. 262 ± 38 min, p=0.002). The main indications for ECMO post-PTE were RVF (61.5%) and reperfusion pulmonary edema (15.3%). Veno-arterial ECMO was used in 69.2% of patients, with 53.8% undergoing peripheral cannulation. The median duration of ECMO was 6 days, with an ICU stay of 14 days and an ICU and hospital mortality rate of 12.5%. Mortality in ECMO-supported patients was 38.4%.

Conclusions: PAPi did not show significant differences between those who required ECMO support postoperatively and those who did not. Further studies with larger patient cohorts are necessary to determine the role of PAPi, using different cutoff points and other hemodynamic variables in the context of PTE.